Introduce opaque_types for the WireCompiler

Author: oldergod

gen-tests.gradle.kts

@@ -213,6 +213,26 @@ val generateAndroidCompactTests by tasks.creating(JavaExec::class) {
   )
 }
 
+// OPAQUE TYPES
+
+val generateOpaqueTypeTests by tasks.creating(JavaExec::class) {
+  group = "Generate Tests"
+  description = "Generates Java, Kotlin, and Swift code to demonstrate opaque types"
+  classpath = wire
+  mainClass.set("com.squareup.wire.WireCompiler")
+  args = listOf(
+    "--proto_path=wire-tests/src/commonTest/proto/kotlin",
+    "--java_out=wire-tests/src/jvmJavaTest/proto-java",
+    "--no_java_exclusive",
+    "--kotlin_out=wire-tests/src/commonTest/proto-kotlin",
+    "--no_kotlin_exclusive",
+    "--swift_out=wire-tests-swift/opaques",
+    "--no_swift_exclusive",
+    "--opaque_types=squareup.protos.opaque_types.OuterOpaqueType.InnerOpaqueType1",
+    "opaque_types.proto"
+  )
+}
+
 // KOTLIN
 
 val generateKotlinTests by tasks.creating(JavaExec::class) {
@@ -493,11 +513,9 @@ val generateSwiftProto2Tests by tasks.creating(JavaExec::class) {
     "custom_options.proto",
     "deprecated.proto",
     "deprecated_enum.proto",
-//      'edge_cases.proto',
     "external_message.proto",
     "foreign.proto",
     "form.proto",
-//      'keyword.proto',
     "map.proto",
     "negative_value_enum.proto",
     "no_fields.proto",
@@ -508,14 +526,11 @@ val generateSwiftProto2Tests by tasks.creating(JavaExec::class) {
     "percents_in_kdoc.proto",
     "person.proto",
     "redacted_one_of.proto",
-//      'redacted_test.proto',
     "recursive_map.proto",
     "same_name_enum.proto",
     "swift_edge_cases.proto",
-//      'simple_message.proto',
     "to_string.proto",
     "unknown_fields.proto"
-//      'uses_any.proto',
   )
 }
 
@@ -714,6 +729,7 @@ val generateTests by tasks.creating {
     generateProto3JavaTests,
     generateProtoReader32KotlinTests,
     generateSharedJson,
+    generateOpaqueTypeTests,
   )
 }
 

wire-compiler/api/wire-compiler.api

@@ -8,6 +8,7 @@ public final class com/squareup/wire/DryRunFileSystem : okio/ForwardingFileSyste
 public final class com/squareup/wire/WireCompiler {
 	public static final field CODE_GENERATED_BY_WIRE Ljava/lang/String;
 	public static final field Companion Lcom/squareup/wire/WireCompiler$Companion;
+	public synthetic fun <init> (Lokio/FileSystem;Lcom/squareup/wire/WireLogger;Ljava/util/List;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Ljava/util/List;Ljava/util/Map;ZZZZZZZIZZZLcom/squareup/wire/kotlin/RpcCallStyle;Lcom/squareup/wire/kotlin/RpcRole;ZLjava/lang/String;ZZZLjava/util/List;Ljava/util/Map;Ljava/util/List;IILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun compile ()V
 	public static final fun forArgs (Ljava/nio/file/FileSystem;Lcom/squareup/wire/WireLogger;[Ljava/lang/String;)Lcom/squareup/wire/WireCompiler;
 	public static final fun forArgs (Lokio/FileSystem;Lcom/squareup/wire/WireLogger;[Ljava/lang/String;)Lcom/squareup/wire/WireCompiler;
@@ -37,6 +38,7 @@ public final class com/squareup/wire/WireCompiler {
 	public final fun getKotlinSingleMethodServices ()Z
 	public final fun getLog ()Lcom/squareup/wire/WireLogger;
 	public final fun getModules ()Ljava/util/Map;
+	public final fun getOpaqueTypes ()Ljava/util/List;
 	public final fun getPermitPackageCycles ()Z
 	public final fun getProtoPaths ()Ljava/util/List;
 	public final fun getSchemaHandlerFactoryClass ()Ljava/lang/String;

wire-compiler/src/main/java/com/squareup/wire/WireCompiler.kt

@@ -98,6 +98,11 @@ import okio.openZip
  *
  * The `--android-annotations` flag will add the `Nullable` annotation to optional fields.
  *
+ * The `--opaque_types` takes a list of qualified named Protobuf types separated by a ','. All types
+ * in the list will be evaluated as being of type `bytes`. On code generation, the fields of such
+ * types will be using the platform equivalent of `bytes`, like [okio.ByteString] for the JVM. Note
+ * that scalar types cannot be opaqued. The opaque step will happen before the tree shaking one.
+ *
  * The `--compact` flag will emit code that uses reflection for reading, writing, and
  * toString methods which are normally implemented with code generation.
  *
@@ -138,6 +143,7 @@ class WireCompiler internal constructor(
   val emitProtoReader32: Boolean,
   val eventListenerFactoryClasses: List<String>,
   val customOptions: Map<String, String>,
+  val opaqueTypes: List<String> = listOf(),
 ) {
 
   @Throws(IOException::class)
@@ -212,6 +218,7 @@ class WireCompiler internal constructor(
       modules = modules,
       permitPackageCycles = permitPackageCycles,
       eventListeners = eventListenerFactoryClasses.map { newEventListenerFactory(it).create() },
+      opaqueTypes = opaqueTypes,
     )
 
     wireRun.execute(fs, log)
@@ -279,6 +286,7 @@ class WireCompiler internal constructor(
     private const val KOTLIN_ESCAPE_KEYWORDS = "--kotlin_escape_keywords"
     private const val EMIT_PROTO_READER_32 = "--emit_proto_reader_32"
     private const val CUSTOM_OPTION_FLAG = "--custom_option="
+    private const val OPAQUE_TYPES_FLAG = "--opaque_types="
 
     @Throws(IOException::class)
     @JvmStatic
@@ -343,6 +351,7 @@ class WireCompiler internal constructor(
       var emitProtoReader32 = false
       var dryRun = false
       val customOptions = mutableMapOf<String, String>()
+      val opaqueTypes = mutableListOf<String>()
 
       for (arg in args) {
         when {
@@ -403,6 +412,14 @@ class WireCompiler internal constructor(
             customOptions[key] = value
           }
 
+          arg.startsWith(OPAQUE_TYPES_FLAG) -> {
+            opaqueTypes.addAll(
+              arg
+                .substring(OPAQUE_TYPES_FLAG.length)
+                .split(','),
+            )
+          }
+
           arg.startsWith(FILES_FLAG) -> {
             val files = arg.substring(FILES_FLAG.length).toPath()
             try {
@@ -503,6 +520,7 @@ class WireCompiler internal constructor(
         emitProtoReader32 = emitProtoReader32,
         eventListenerFactoryClasses = eventListenerFactoryClasses,
         customOptions = customOptions,
+        opaqueTypes = opaqueTypes,
       )
     }
   }

wire-compiler/src/test/java/com/squareup/wire/WireCompilerTest.kt

@@ -345,6 +345,17 @@ class WireCompilerTest {
     assertJavaOutputs(outputs)
   }
 
+  @Test
+  fun testOpaqueTypes() {
+    val sources = arrayOf("opaque_types.proto")
+    compileToKotlin(sources, "--opaque_types=squareup.protos.opaque_types.OuterOpaqueType.InnerOpaqueType1")
+
+    val outputs = arrayOf(
+      "squareup/protos/opaque_types/OuterOpaqueType.kt",
+    )
+    assertKotlinOutputs(outputs)
+  }
+
   @Test
   fun testCustomOptionsNoOptions() {
     val sources = arrayOf("custom_options.proto", "option_redacted.proto")